It is easy to get known that the pigmentation of the eye's iris and the frequency-dependence of the scattering in the stroma of the iris decide our eye colors. Eye color is permanent so that you must take some artificial ways to change it if you want to do. Well, if your eyes change into yellow, the most possible factor is something wrong with your eyes or liver. The best thing to do is call a doctor for help. You need to receive thorough eye exam and determine the real reasons for your condition. Plus, it is said that too much vitamin A in body will also cause yellow in eyes and skin.
Yellow eyes can be a sign of jaundice, which can result from temporary or permanent liver damage. Any number of liver-metabolized drugs taken in sufficient quantities can have this effect if normal enzyme levels are disrupted. However, they are not permanent, when the liver recovers, the color goes back to normal. (Not sure about hepatitis because it's a chronic condition.)
If liver imbalance is the culprit, I would imagine this is most likely the result of someone having taken many vicodin or other prescription opiate that contains APAP, as the large amount of acetaminophen (APAP, generic name for tylenol) present can cause liver problems.
On the other hand, yellow eyes can be cause by sleep deprivation, which might be the result of amphetamine or a similar substance.
I suggest that maybe you can have a good rest.
Of course yellow eyes are not permanent. If your eyes white takes a yellowish tinge, it is jaundice to be blamed for. It happens because of the bilirubin built up in blood, which is yellow pigmented, coming from the break down of old red blood cells. If you have yellow eyes, you should go to hospital immediately to have a detailed blood examination. Usually it is related to icterohepatitis, cholangitis, septicemia or some other serious disease. It could be lethal if you don't get treatment. I once got yellow eyes and yellow skin for icterohepatitis, and it took over one month to clear the discoloration out.